Electrical resistance device



I Q INVENTOR Nov. 10, 1936. w. J. HlscocK ELECTRICAL RESISTANCE DEVICE Filed June 23, 1954 Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE ELECTRICAL RESISTANCE DEVICE ration of Maine Application June 23, 1934, Serial No. 732,131

3 Claims.

The present invention relates to electrical resistance or suppressor devices for eliminating or suppressing the high frequency oscillations generated at the spark plugs or in various portions of the ignition or other circuits of internal combustion motors, for preventing interference with the operation of adjacent radio receiving sets, one object being to provide an eflicient suppressor device of simplified, compact and efiicient construction, capable of being readily interposed in such a circuit.

Another object of the invention is to provide a unitary device of the above character, having an improved construction and arrangement of parts designed to increase the effective length of the resistance element and to afford a greater separation of the terminals, whereby to improve the voltage coefficient of said element and prevent sparking between the terminals, as well as to generally improve and afford other advantages in devices of this character, well understood in the art.

Another object is the provision of a device of the above character particularly adapted for application to the spark plugs of an internal combustion motor.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawing:

Fig. 1 is a view in elevation and partly in section showing a spark plug having attached thereto the resistor unit shown in Fig. 2;

Fig. 2 is a sectional elevation of one form of resistor unit shown attached to the threaded terminal of a spark plug;

Fig. 3 is a somewhat similar View of a slightly modified form of the invention;

Fig. 4 is a sectional elevation of another modification of the resistor unit, and

Fig. 5 is a sectional elevation of still another resistor unit somewhat similar to that shown in Fig. 4.

The same reference numerals throughout the several views indicate the same parts.

Referring to the drawing, l0 designates a 50 portion of the cylinder block of an internal combustion engine having a well H formed therein and within which is disposed a spark plug designated generally by the reference character [2. Connected with the spark plug is a resistor unit l3 of the type shown in Fig. 2, but in place of which may be substituted either of the modications shown in. Figs. 3 to 5, inclusive.

The resistor unit shown in Fig. 2 comprises a support or body member l4 formed of any suitable insulating material such, for example, as Bakelite which is preferably moulded while in a plastic state within and about the metal contacts l5 and I6, respectively, to rigidly secure them upon the body member.

The outer contact member [5 is tapered to facilitate the insertion thereon of a terminal ll with which is connected a cable or conductor l8 adapted to be connected with the ignition circuit of an internal combustion engine or with any suitable type of circuit controlling means therefor. The terminal I! may be of the split sleeve type or of any other suitable design, the finger-like portions 19 of which yieldingly engage the grooved or reduced portion 20 of the outer contact member located between the ends of said member whereby to insure proper contact between the parts while at the same time preventing accidental displacement of the terminal.

The contact member I6 anchored within the body member I4 is interiorly threaded to receive the threaded post or terminal 2| of the spark plug l2. The resistance element 22 which may be formed of any suitable material capable of affording the desired resistance extends longitudinally v within the outer end of the body member and is supported therein by a metal plug 23 screwed into the contact member I6 before securing the latter upon the spark plug terminal 2|.

A spring 24 is interposed between the resistance element and the outer end portion [5b of the contact member to urge said element in engagement with the metal plug 23 whereby to insure proper contact between the latter and the resistance element. However, if preferred, the spring may be positioned between the plug 23 and the resistance element in which case the latter will directly engage the outer transverse portion I51) of the contact member [5. As a substitute for the plug 23, solder may be used to form a bond between the end of the contact l6 and the resistance element 22, the soldering operation being efiected before securing the contact member in position upon the spark plug terminal.

It will be noted that the longitudinally extending portion of the contact member I5 is in overlapping relation with respect to the resistance element and that the outer end of the resistance element is placed in close proximity to, and if preferred may be made to contact with the transverse end portion |b of the terminal receiving contact member IS, the side walls of the latter being held in spaced relation to the resistance element by the moulded material of the body member lying between said parts.

By extending the contact member l5 upon the support or body member in overlapping relation with respect to the resistance element, the latter can be extended the entire distance between the end portions of the contacts l5 and 6 whereby to increase the effective length of the resistance element. In other words, with the design shown in Figs. 2 and 3, the use of a relatively long resistance element is made possible within a support or body member of comparatively short length, and this is advantageous since it is important to provide a relatively long resistance element in order to improve the voltage coefficient thereof and to increase the length between the contacts, whereby to avoid the danger of a disruptive or Jump spark between the same.

A further advantage of the design shown in Figs. 2 and 3, is that by placing the inner contact l6 within the body member and adapting it for the reception of the terminal of the spark plug the overall length of the unit is considerably reduced whereby it may be used with installations afiording but comparatively little space for its application.

A further advantage in this design is that it permits the resistance element to be placed relatively close to the spark gap, which is important from the standpoint of efficiency and best results in suppressing the high frequency oscillations generated by the spark whereby to eliminate the undesirable noises in various radio receiving sets, this being also true of the different modifications shown.

It will be understood that the present resistor unit is designed to suppress or eliminate the noises produced by sparking, not only in the radio set installed in the car provided with the resistor unit, but also in other radio sets whether the latter are installed in motor vehicles, residences, or elsewhere.

The unit |3a shown by the modification of Fig. 3 is similar to that shown in Fig. 2 in that the outer contact |5a is telescoped upon the outer end of the support Ma and is in overlapping relation with respect to the resistance element 22a, while the inner contact |6a extends within the base of the support and is threaded to receive the terminal 2| of the spark plug, as shown, the advantages of this arrangement of parts being the same as those described in connection with the similar arrangement shown in Fig. 2.

The inner contact |6a is rigidly secured within the support or body member by moulding the material thereof about said contact. The outer contact |5a has the material of the body member moulded therein, said contact having its inner end extended into the enlarged base portion of the body member in which it is anchored by the flange lie about which the material of the body member is moulded.

The outer contact |5a has a groove or reduced portion 20a similar to the reduced portion 20 of the contact I5 and provided for the same purpose, namely, to receive the spring-like portions I9 01' the terminal IT, as shown in Fig. 1.

In the design shown in Fig. 3, the outer end of the body member is provided with a metal disk 25 which is secured in position thereon by the inwardly turned flange-like. portion 26 of the contact l5a, said portion being preferably formed by a spinning operation effected by the use of a suitable tool for turning inwardly the tapered end of the contact l5a. as shown.

In this design the outer end of the resistance element 22a is urged into engagement with the metal disk 25 by a spring 21 interposed between its inner end and the end wall of the contact Ilia and electrically connecting the same. As stated above, the unit shown in Fig. 3 is adapted to receive the terminal I! of the cable l8 and it also has the advantage of a relatively long resistance element positioned relatively close to the spark plug as well as the advantage of a compact or short body portion which will occupy comparatively little space.

In the modification shown in Fig. 4 the threads of the body member 28, which are adapted to receive those of the terminal 2| of the spark plug, are formed by moulding them within the material of said body member as indicated at 29. The resistance element 30 is disposed laterally of or at one side of the spark plug terminal 2| in substantially parallel relation thereto and extends substantially the full length of the support or body member. The latter has an extension 3| on its outer end upon which is telescoped a metal contact member 32 secured in position by moulding the material of the support therein. The metal contact 32 is designed for connection with a distributor or other circuit controlling means through the medium of a terminal and conductor similar to that shown at ||--|8 in Fig. 1, the terminal being adapted for ready insertion upon and removable from the contact 32.

The inner contact member 33 is in the form of a metal plate having an opening therein for the passage therethrough of the spark plug terminal 2|. The plate 33 is provided with a plurality of outwardly extending tongue-like portions 34 disposed in surrounding relation with respect to said opening and about which the material of the body member is moulded and by which the plate is rigidly anchored upon the body member.

The plate is provided with an opening 35 of slightly larger diameter than that of the resistance element and through which the latter is inserted. The outer end of the resistance element is urged into engagement with the end portion 32a of the contact 32 and may be secured in position by any suitable means as, for example, by the use of solder as indicated at 36, the solder contacting the inner end of the resistance element and forming a bond between the latter and the plate 33.

In this form of resistor unit the metal plate is electrically connected with the spark plug by reason of the fact that it is seated on the end of the metal part 31 of the plug which supports the threaded terminal 2|. Furthermore, in this modification a relatively long resistance element is afforded which extends into close proximity to the spark plug, which is important and advantageous for the reasons above stated.

In the modification shown in Fig. 5, the principle of operation is the same as that shown in Fig. 4. In this design the support or body member 38 is formed of suitable insulating material which is moulded about the threaded contact member 39 for receiving the terminal 2| of the spark plug. The contact 39 is seated upon the metal portion 31 of the spark plug and has a lateral extension 40 in which is formed an opening 4| through which the resistance element 42 is inserted, said element being secured preferably by means of the solder indicated at 43, which forms a bond between the resistance element and the extension 40 of the contact 39.

The outer end of the resistance element engages a plate-like extension 44 on the contact 45, the latter being rigidly secured on the body member by moulding the material thereof within said contact and also by moulding a portion of the material in surrounding relation with respect to the plate-like extension 44. The metal contact 45 is adapted to detachably receive the terminal I1 shown in Fig. 1.

One advantage of the designs shown in Figs. 4 and 5 is that by offsetting or spacing the. resistance element laterally of the spark plug terminal or socket for receiving the same, the inner end of the resistance element can be positioned relatively close to the spark gap which is important and advantageous from the standpoint of efficiency of the unit as a means for suppressing the high frequency oscillations generated by the spark.

In the modification shown in Fig. 4, the effective length of the resistance element is considerably increased by offsetting it with respect to the terminal receiving portion of one of the contacts and telescoping it within the other contact while at the same time maintaining it in what may be termed co-extensive relation with respect to said terminal receiving portions. This is also true of the arrangement shown in Fig. 5 in which the resistance element is offset relative to the terminal receiving portions of both contacts but maintained in co-extensive relation with respect thereto although connected with the laterally extending portions thereof.

The advantage of the arrangements shown in Figs. 4 and 5, as previously stated, is to aiford a greater separation for the contacts to increase the length and improve the voltage coefficient of the resistance element and prevent sparking over, it being understood that the same advantages are also afforded by the devices shown in Figs. 2 and 3 of the drawing.

In each of the designs shown the resistor unit can be readily applied to and removed from the spark plug merely by screwing it upon or unscrewing it from the threaded terminal 2| of the plug.

I claim:-

1. An electrical suppressor device, comprising an elongated body member of insulating material, said body member being recessed at its inner end and having a bore extending from said recess longitudinally through the remainder of the body member, said recess having anchored therein an interiorly threaded contact for the reception of an electric terminal, an outer contact telescoped upon the body member and extending longitudinally thereon for a considerable portion of the length of the body member and having its inner end embedded within the material of the body member, and a resistance element extending longitudinally within said bore and electrically connected adjacent its ends with the respective contacts, a substantial portion of the effective length of the resistance element being telescoped within and insulated from said outer contact by said body member except at its connection therewith, said outer contact having formed thereon an inwardly offset portion substantially encircling said body member and in interlocking engagement therewith at a point between the ends of the resistance element and affording a groove for the telescopic reception of an electric terminal element.

2. An electrical suppressor device, comprising an elongated body member of insulating material having a longitudinally extending bore, a metal contact telescoped upon one end of the body member and having an outer end. portion closing said bore and an inner end portion anchored within the material of the body member, said contact being formed between the ends of the body member with an encircling offset portion for telescopic reception of a circuit terminal, a

second metal contact anchored within the opposite end of the body member and having a recess for the reception of another circuit terminal, and a resistance element extending longitudinally within said bore and electrically connected adjacent its ends with the respective contacts, a substantial portion of the effective length of the resistance element being telescoped within the first mentioned contact and insulated therefrom by the body member except at said connection therewith to afford a greater separation of said contacts to increase the length of said resistance element and prevent sparking over.

3. An electrical suppressor device, comprising an elongated body member of insulating material having a reduced portion at one end, said body member having a longitudinally extending bore in the last mentioned end terminating in an enlarged recess formed within the opposite end of the body member, a metal contact anchored within said recess and adapted for the reception of an electric terminal, a second metal contact telescoped upon the reduced end portion of the body member and provided at its inner end with an offset securing portion embedded within the material of the body member, said second contact being grooved between its ends for the reception of an electric terminal, a metal part seated on the outer extremity of said reduced end portion of the body member and forming a closure for said bore, said telescoping contact having an inwardly turned part overlying the outer face of said metal part and securing the latter upon the body member, and a resistance element extending longitudinally within said bore and electrically connected at one end with said metal part and at its opposite end with the contact disposed within said recess, a substantial portion of the effective length of the resistance element being co-extensive with and insulated from said second contact except through connection with said metal part whereby to afford greater separation for said contacts.

WILLIAM J. HISCOCK. 

